Add lazy vals for complicated calculations

JetBrains · Apr 16, 2021 · 5ff6d62 · 5ff6d62
1 parent c7895cd
commit 5ff6d62
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Showing 3 changed files with 43 additions and 17 deletions.
diff --git a/src/main/java/org/jetbrains/bsp/bazel/commons/Lazy.java b/src/main/java/org/jetbrains/bsp/bazel/commons/Lazy.java
@@ -0,0 +1,18 @@
+package org.jetbrains.bsp.bazel.commons;
+
+import java.util.Optional;
+import java.util.function.Supplier;
+
+public abstract class Lazy<T> {
+  private Optional<Optional<T>> value = Optional.empty();
+
+  protected abstract Supplier<Optional<T>> calculateValue();
+
+  public Optional<T> getValue() {
+    if (value.isEmpty()) {
+      value = Optional.of(calculateValue().get());
+    }
+
+    return value.get();
+  }
+}
diff --git a/src/main/java/org/jetbrains/bsp/bazel/server/bsp/managers/BazelBspJvmTargetManager.java b/src/main/java/org/jetbrains/bsp/bazel/server/bsp/managers/BazelBspJvmTargetManager.java
@@ -5,20 +5,21 @@
 import com.google.devtools.build.lib.query2.proto.proto2api.Build;
 import java.util.List;
 import java.util.Optional;
+import java.util.function.Supplier;
+import org.jetbrains.bsp.bazel.commons.Lazy;
 import org.jetbrains.bsp.bazel.commons.Uri;
 import org.jetbrains.bsp.bazel.server.bazel.BazelProcess;
 import org.jetbrains.bsp.bazel.server.bazel.BazelRunner;
 import org.jetbrains.bsp.bazel.server.bazel.params.BazelRunnerFlag;
 import org.jetbrains.bsp.bazel.server.bsp.resolvers.QueryResolver;
 
-public class BazelBspJvmTargetManager {
+public class BazelBspJvmTargetManager extends Lazy<String> {
   public static final String FETCH_JAVA_VERSION_ASPECT =
       "@//.bazelbsp:aspects.bzl%fetch_java_target_version";
   public static final String BAZEL_JDK_CURRENT_JAVA_TOOLCHAIN =
       "@bazel_tools//tools/jdk:current_java_toolchain";
   private final BazelRunner bazelRunner;
   private BazelBspAspectsManager bazelBspAspectsManager;
-  private String javaVersion;
 
   public BazelBspJvmTargetManager(
       BazelRunner bazelRunner, BazelBspAspectsManager bazelBspAspectsManager) {
@@ -79,20 +80,20 @@ private Optional<Build.Target> getTargetFromAttribute(Build.Attribute attribute)
   }
 
   private Optional<String> getJavaVersion() {
-    if (javaVersion == null) {
-      bazelBspAspectsManager
-          .fetchLinesFromAspect(BAZEL_JDK_CURRENT_JAVA_TOOLCHAIN, FETCH_JAVA_VERSION_ASPECT)
-          .filter(
-              parts ->
-                  parts.size() == 3
-                      && parts.get(0).equals(BazelBspAspectsManager.DEBUG_MESSAGE)
-                      && parts.get(1).contains(BazelBspAspectsManager.ASPECT_LOCATION)
-                      && parts.get(2).chars().allMatch(Character::isDigit))
-          .map(parts -> parts.get(2))
-          .findFirst()
-          .ifPresent(version -> this.javaVersion = version);
-    }
+    return bazelBspAspectsManager
+        .fetchLinesFromAspect(BAZEL_JDK_CURRENT_JAVA_TOOLCHAIN, FETCH_JAVA_VERSION_ASPECT)
+        .filter(
+            parts ->
+                parts.size() == 3
+                    && parts.get(0).equals(BazelBspAspectsManager.DEBUG_MESSAGE)
+                    && parts.get(1).contains(BazelBspAspectsManager.ASPECT_LOCATION)
+                    && parts.get(2).chars().allMatch(Character::isDigit))
+        .map(parts -> parts.get(2))
+        .findFirst();
+  }
 
-    return Optional.ofNullable(javaVersion);
+  @Override
+  protected Supplier<Optional<String>> calculateValue() {
+    return this::getJavaVersion;
   }
 }
diff --git a/src/main/java/org/jetbrains/bsp/bazel/server/bsp/managers/BazelBspScalaTargetManager.java b/src/main/java/org/jetbrains/bsp/bazel/server/bsp/managers/BazelBspScalaTargetManager.java
@@ -6,11 +6,13 @@
 import com.google.common.collect.ImmutableList;
 import java.util.List;
 import java.util.Optional;
+import java.util.function.Supplier;
 import java.util.stream.Collectors;
 import org.apache.logging.log4j.LogManager;
 import org.apache.logging.log4j.Logger;
+import org.jetbrains.bsp.bazel.commons.Lazy;
 
-public class BazelBspScalaTargetManager {
+public class BazelBspScalaTargetManager extends Lazy<ScalaBuildTarget> {
   private static final Logger LOGGER = LogManager.getLogger(BazelBspScalaTargetManager.class);
 
   public static final String SCALA_LIBRARY =
@@ -64,4 +66,9 @@ protected Optional<ScalaBuildTarget> getScalaBuildTarget() {
 
     return Optional.of(scalaBuildTarget);
   }
+
+  @Override
+  protected Supplier<Optional<ScalaBuildTarget>> calculateValue() {
+    return this::getScalaBuildTarget;
+  }
 }